Machine Type Communications (MTC) are expected to contribute heavily to connectivity and traffic within the mobile broadband industry. The GSM/EDGE system already serves a rapidly expanding market for MTC. Mobile communications operators have expressed interest in accommodating traffic that serves wireless sensors/devices within modern evolved networks such as those based on LTE. As part of this, it would be incumbent on them to handle MTC traffic served by existing cellular networks such as GSM/EDGE and to provide a transition for such traffic from e.g. GPRS/EDGE to future versions of cellular systems, such as 3GPP Long Term Evolution Advance (LTE-A, or LTE-Advanced).
Wireless sensor networks have gained increasing interest from academia and industry. Such networks have, however, predominantly been built around short range communication links, such as those based on Bluetooth, and more recently on the Zigbee standard. It is of particular interest to examine whether existing and future cellular systems can be modified to efficiently accommodate the traffic from these wireless sensor devices. This is a challenging task considering that (1) the latest versions of existing cellular systems, 3GPP systems, such as High Speed Packet Access (HSPA), LTE, or LTE-A, or IEEE systems, such as 802.16 (WiMax), are conceived primarily with the goal of providing service mainly to mobile broadband users and (2) there is a requirement from operators that these wireless devices (sensors) are low cost and have high energy efficiency.
Signaling mechanisms in existing and future 3GPP and IEEE networks have been conceived with the intention of securing a robust connection/session lasting for long periods of time, and involving transmission of large data volumes. In this respect, signaling mechanisms and protocols involving several long messages amounting to hundreds or thousands of kilobytes of data are not considered as particularly significant overhead when compared to the amount of data traffic exchanged within a session.
However, many wireless sensor devices are expected to transmit with very low activity and with long periods of inactivity between transmissions. Also, such devices typically transmit small amounts of information—typically a few hundred octets of data, indicating, e.g. a measurement, or presence. Some wireless sensor devices serve as actuating receivers, where a short message from the network of a few hundred octets of data may need to be processed and acted on. The existing signaling mechanisms for establishing and maintaining a connection are considered as considerably “heavy” for such device types or application categories, and there is a real concern that the volume of signaling traffic can quickly overwhelm the cellular network. In other words, the signaling overhead is no longer negligible for very small transmissions. In addition, keeping a connection up or reestablishing a connection on wake-up may constitute an undue burden on a device with a targeted battery life that spans years.
In the most common scenario, devices are anticipated to transmit in uplink a single packet containing measurements, warnings, or other types of information to the cellular network. Hence, data transmissions occur mainly in the uplink, while the downlink serves mainly for transmitting feedback and link control information to devices.
In this respect, entire radio network interfaces and radio resource management algorithms require new approaches. However, in order to perform these modifications to radio protocol architectures and to radio resource management (RRM), there is a need to have information on the network side regarding some characteristics of machine devices related to their capabilities, including, for example, their mobility pattern, energy supply, and traffic pattern. An RRM algorithm that may be important for efficient use of radio resources in the system and which may affect the energy consumption of machine devices and/or user equipment may include Intercell Interference Coordination (ICIC).
Existing ICIC mechanisms may be autonomous in which decisions are performed internally or coordinated in which neighbor base stations coordinate their transmissions via explicit signaling. Messages exchanged for ICIC purposes, however, may not provide awareness to neighboring cells that certain physical resource blocks and/or time slots may have high levels of sensitivity to other cell interference due to limited complexity and energy management of sensors and/or other devices.
A standardized message may be exchanged between neighboring cells for ICIC. For example, as described in §9.1.2.1 of 3GPP TS 36.423, version 11.1.0, which is incorporated by reference herein in its entirety, a “Load Information” message may be used to exchange messages between neighboring cells for ICIC purposes. The “Load Information” message may include, for example, Informational Elements (IEs) “UL Interference Overload Indication” and “UL High Interference Indication”, among others. Both messages may be related to uplink interference, which may be particularly beneficial in the context of a UE having greater uplink traffic, such as machine type communications (MTC).
The IE “UL Interference Overload Indication” is a message that may be transmitted from a given cell 110 to its neighboring cells 110 when a high level of uplink interference in certain physical resource blocks (PRBs) is experienced. In this regard, the “UL Interference Overload Indication” may generally be a reactive ICIC mechanism and thus less effective at preventing cell interference.
The IE “UL High Interference Indication” is a message transmitted from a given cell 110 to its neighboring cells 110 and may indicate the PRBs in which high interference sensitivity may exist. As such, neighboring cells 110 are notified of the PRBs that are vulnerable and may be easily affected by other cell interference.
Both the “UL Interference Overload Indication” and the “UL High Interference Indication” IEs may be used to perform ICIC for MTC. However, the “UL Interference Overload Indication” IE is not preventative. Additionally, although the “UL High Interference Indication” may be used for the PRBs and timeslots for which wireless devices such as sensors are scheduled, neighboring cells 110 may not be aware of the sensitivity to other cell interference that may be increased by low complexity and/or low power wireless devices.
Accordingly, there is a need for a method and device for operating a radio network node to provide ICIC for machine to machine communications.
The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.